Imidatosilanes

ABSTRACT

Compound of the formula: WHEREIN R1 and R7 are each organic radicals of not more than 18 carbon atoms selected from the group consisting of hydrogen, hydrocarbyl, halohydrocarbyl and cyanoalkyl, R and R2 are each organic radicals of not more than 18 carbon atoms selected from the group consisting of hydrocarbyl, halohydrocarbyl, nitrohydrocarbyl and alkoxyhydrocarbyl, R3 is an organic radical of not more than 18 carbon atoms selected from the group consisting of hydrogen, hydrocarbyl, halohydrocarbyl, nitrohydrocarbyl, alkoxyhydrocarbyl, dialkylamino and WHEREIN R4 is an organic radical selected from the group consisting of aliphatic hydrocarbyl, aliphatic halohydrocarbyl, aliphatic nitrohydrocarbyl, and WHEREIN R5 and R6 are each aliphatic hydrocarbyl, a is an integer of 1 to 4, inclusive, b is an integer of 0 to 3, inclusive, d and e are each integers of 0 to 1, and the sum of a, b, d and e is 4. The imidatosilanes are useful as chain extenders and as curing agents in one-package RTV compositions.

United States Patent Evans [451 May 23, 1972 54] IMIDATOSILAN ES [72]Inventor: Milton L. Evans, Schenectady, NY.

[73] Assignee: General Electric Company [22] Filed: Mar. 14, 1969 [21]Appl.No.: 807,436

[52] US. Cl ..260/448.8 R, 260/4482 N, 260/25 [5 1 Int. Cl ..C07f 7/02,C07f 7/04 [58] Field of Search ..260/448.2 N, 448.8 R

[56] References Cited UNTTED STATES PATENTS 2,876,209 3/1959 Bennevilleet a] "260/4482 N 2,876,234 3/1959 Hurwitz et a1 ...260/448.2 N3,488,371 1/1970 Klebe ..260/448.2 N

Primary ExaminerTobias E. Levow Assistant Examiner-Werten F. W. BellamyAttorneyDonavon L. Favre, Frank L. Neuhauser and Oscar B. WaddellABSTRACT Compound of the formula;

R3 (R0 J=N) a (R )d wherein R is an organic radical selected from thegroup consisting of aliphatic hydrocarbyl, aliphatic halohydrocarbyl,aliphatic nitrohydrocarbyl. and

wherein R and R are each aliphatic hydrocarbyl. u is an integer of 1 to4, inclusive, b is an integer of 0 to 3. inclusive. d and e are eachintegers of 0 to l, and the sum of a, b, d and e is 4. Theimidatosilanes are useful as chain extenders and as curing agents inone-package RTV compositions.

16 Claims, N0 Drawings IMIDATOSILANES This invention relates toimidatosilanes and methods for their preparation. The imidatosilanes ofthis invention are useful in the preparation of one-package roomtemperature vulcanizing (RTV) compositions, as chain extenders forsilanolstopped polydiorganosiloxanes and as plasticizers for RTVcompositions.

The imidatosilanes of this invention are represented by the formula:

wherein R and R are each organic radicals of not more than 18 carbonatoms selected from the group consisting of hydrogen, hydrocarbyl,halohydrocarbyl and cyanoalkyl, R and R are each organic radicals of notmore than 18 carbon atoms selected from the group consisting ofhydrocarbyl, halohydrocarbyl, nitrohydrocarbyl and alkoxyhydrocarbyl, Ris an organic radical of not more than 18 carbon atoms selected from thegroup consisting of hydrogen, hydrocarbyl, halohydrocarbyl,nitrohydrocarbyl, alkoxyhydrocarbyl, dialkylamino and wherein R is anorganic radical selected from the group consisting of aliphatichydrocarbyl, aliphatic halohydrocarbyl, aliphatic nitrohydrocarbyl, and

wherein R and R are each aliphatic hydrocarbyl, a is an integer of l to4, inclusive, 1; is an integer of 0 to 3, inclusive, d and e are eachintegers of 0 or 1, and the sum of a, b, d and e is 4.

The term hydrocarbyl as used herein means a hydrocarbon from which onehydrogen atom has been removed, i.e., a monovalent hydrocarbon.

In the above formula, preferably, R and R are H, phenyl or alkyl of notmore than 4 carbon atoms, R and R are phenyl or alkyl or allyl oralkoxyalkyl of not more than 8 carbon atoms and R is phenyl or alkyl ofnot more than 4 carbon atoms.

In the above formula, R and R can be, for example, mononuclear andbinuclear aryl, such as phenyl, naphthyl, benzyl, tolyl, xylyl,2,6-di-t-butylphenyl, 4-butylphenyl, 2,4,6- trimethylphenyl, biphenyland ethylphenyl; halogen-substituted mononuclear and binuclear aryl suchas 2,6- dichlorophenyl, 4-bromophenyl, 2,5-difluorophenyl, 4,4-dichlorobiphenyl, 2-chloronaphthyl, 2,4,6-trichlorophenyl and2,5-dibromophenyl; nitro-substituted mononuclear and binuclear aryl suchas 4-nitrophenyl and 2,6-dinitrophenyl; alkoxy-substituted mono andbinuclear aryl such as 4-methoxyphenyl, 2,6-dimethoxyphenyl,4-t-butoxyphenyl, 2-ethoxyphenyl, 2-ethoxynaphthyl and2,4,6-trimethoxyphenyl; alkyl such as methyl, ethyl, n-propyl,isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, amyl, hexyl,heptyl, octyl, nonyl, decyl, dodecyl and the various homologs andisomers of alkyl of not more than 18 carbon atoms, alkenyl such asvinyl, ally], n-butenyl-l n-butenyl-2, n-pentenyl-Z, n-hexenyl-2,2,3-dimethylbutenyl-Z, n-heptenyl, n-decenyl, n-dodecenyl and thevarious homologs and isomers of alkenyl of not more than 18 carbonatoms; alkynyl such as propargyl, Z-butynyl and the various homologs andisomers of alkynyl of not more than 18 carbon atoms; haloalkyl such aschloromethyl, iodomethyl,

bromomethyl, fluoromethyl, chloroethyl, iodoethyl, bromoethyl,fluoroethyl, trichloromethyl, diiodoethyl, tribromomethyl,trifluoromethyl, dichloroethyl, chloro-npropyl, bromo-n-propyl,iodoisopropyl, bromo-n-butyl, bromo-tert-butyl, 1,3,3-trichlorobutyl,1,3,3-tribromobutyl, chloropentyl, bromopentyl, 2,3-dichloropentyl, 3,3-dibromopentyl, chlorohexyl, bromohexyl, 2,4-dichlorohexyl, l,3-dibromohexyl, 1 ,3 ,4-trichlorohexyl, chloroheptyl,

bromoheptyl, fluoro-heptyl, 1,3-dichloroheptyl, 1,4,4- trichloroheptyl,2,4-dichloromethylheptyl, chlorooctyl, bromooctyl, iodooctyl,2,4-dichloromethylhexyl, 2,4-

dichlorooctyl, 2,4,4-trichloromethylpentyl, 1,3,5-tribromooctyl and thevarious homologs and isomers of haloalkyl of not more than 18 carbonatoms; haloalkenyl such as chlorovinyl, bromovinyl, chloroallyl,bromoallyl, 3-chloro-n-butenyl-l, 3- chloro-n-pentenyl- 13-fluoro-n-heptenyl-l l ,3,3-trichloro-nheptenyl-S1,3,5-trichloro-n-octenyl-6, 2, 3 ,3- trichloromethylpentenyl-4 and thevarious homologs and isomers of haloalkenyl of not more than 18 carbonatoms; haloalkynyl such as chloropropargyl, bromopropargyl and thevarious homologs and isomers of haloalkynyl of not more than 18 carbonatoms; nitroalkyl such as nitromethyl, nitroethyl, nitro-n-propyl,nitro-n-butyl, nitropentyl, 1,3-dinitroheptyl and the homologs andisomers of nitroalkyl of not more than 18 carbon atoms; nitroalkenylsuch as nitroallyl, 3-nitro-n-butenyl-l, S-nitro-n-heptenyl-l and thevarious homologs and isomers of nitroalkenyl of not more than 18 carbonatoms; nitroalkynyl such as nitropropargyl and the various homologs andisomers of nitroalkynyl of not more than 18 carbon atoms; alkoxyalkyland polyalkoxyalkyl such as methoxymethyl, ethoxymethyl, butoxymethyl,methoxyethyl, ethoxyethyl, ethoxyethoxyethyl, methoxyethoxymethyl,butoxymethoxyethyl, ethoxybutoxyethyl, methoxypropyl, butoxypropyl,methoxybutyl, butoxybutyl, methoxypentyl, butoxypentyl,methoxymethoxypentyl, butoxyhexyl, methoxyheptyl, ethoxyethoxy and thevarious homologs and isomers of alkoxyalkyl and polyalkoxyalkyl of notmore than 18 carbon atoms; alkoxyalkenyl and polyalkoxyalkenyl such asethoxyvinyl, methoxyallyl, butoxyallyl, methoxy-n-butenyll,butoxy-n-pentenyl-l methoxyethoxy-n-heptenyl-l, and the various homologsand isomers of alkoxyalkenyl and polyalkoxyalkenyl of not more than 18carbon atoms; alkoxyalkynyl and polyalkoxyalkynyl such asmethoxypropargyl and the various homologs and isomers of alkoxyalkynyland polyalkoxyalkynyl of not more than 18 carbon atoms; cycloalkyl,cycloalkenyl and alkyl, halogen, alkoxy and nitro-substituted cycloalkyland cycloalkenyl such as cyclopentyl, cyclohexyl, cycloheptyl,cyclooctyl, cyclononyl, 6-methylcyclohexyl, 2,5-dimethylcycloheptyl, 4-

butylcyclopentyl, 3,4-dichlorocyclohexyl, 2,6-dibromocycloheptyl,6-methoxycyclooctyl, 2-nitrocyclopentyl, lcyclopentenyl, 3-methyl- 1-cyclopentenyl, S-methoxy- 1 cyclopentenyl, 3 ,4-dimethyll-cyclopentenyl, 2,5 -dimethoxyl-cyclopentenyl, S-methyl-S-cyclopentenyl,3,4-dichloro-5- cyclopentenyl, 5-(tert-butyl)- l -cyclopentenyl,2-nitrol cyclohexenyl, l-cyclohexenyl, 3-methyl-1-cyclohexenyl, 3,4-dimethyl-l-cyclohexenyl, 6-methoxy-l'cyclohexenyl and the like.

In the above formula, the hydrocarbyl and substituted hydrocarbyl of R,R, R and R can be those listed above for R and R In the above formula, Rand R" can be hydrogen, hydrocarbyl and halohydrocarbyl such as thoselisted above for R and R and cyanoalkyl such as cyanomethyl, cyanoethyl,cyanobutyl, cyanoisobutyl and the various isomers and homologs ofcyanoalkyl of not more than 18 carbon atoms.

The imidatosilanes of this invention are prepared by a process whichcomprises reacting an organic compound selected from the groupconsisting of 1) an imidate and (2) a mixture of an imidate and analcohol with a silane of the formula:

SIX! (R6.

in the presence of an acid acceptor. The process of this invention canbe represented by the following synthesis:

R3 R aR( 3=NH bROH 81X: (RO( J=N-)A)R )d wherein R, R, R R, R", a, b, dand e are as defined above, X is halogen (Cl, Br, F or I) andfis aninteger from 2 to 4, inclusive. ln carrying out the process of thisinvention, the organic compound and the silane can be added separatelyor concomitantly to the reaction vessel in the required amounts or amolar excess of either reactant can be used. if excess reactant isemployed, it is preferred that it be the organic compound since it willserve as a reaction medium and is easily separated from the product.Temperature of reaction for the process of this invention is notcritical and good results can generally be obtained at a temperaturefrom about 0 C to about 100 C. Temperatures from about 25 C to about 80C are preferred.

The process is preferably carried out in the presence of an inertorganic medium. The organic medium which can be employed in the processof this invention can be any of the Well known solvents and diluentswhich are inert to the reactants. For example, aromatic hydrocarbons,such as benzene, toluene and xylene; ethers such as diethyl ether,dibutyl ether, bis-( 2-methoxyethyl)-ether and tetrahydrofuran; cyclichydrocarbons, such as cyclohexane; nitriles such as acetonitrile andamides such as dimethylacetamide.

The separation of the product from the reaction mixture is readilyaccomplished by conventional means well known in the art. For examplefiltration, fractional distillation under reduced pressure, selectiveextraction, fractional distillation using a carrier gas, filmdistribution, elution or any appropriate combination of these methodsare suitable.

Pressure is not a critical factor in the process of this invention.Pressure both above and below atmospheric pressure can be employed,although atmospheric pressure is preferred for convenience.

Acid acceptors which can be used in the process of this inventioninclude the following representative materials. Inorganic bases, forexample, alkali-metal hydroxides such as lithium hydroxide, sodiumhydroxide, potassium hydroxide, rubidium hydroxide and cesium hydroxide;alkaline earth metal hydroxides such as calcium hydroxide and bariumhydroxide; alkali-metal hydrides such as sodium hydride, potassiumhydride and lithium hydride; metallic oxides such as calcium oxide,magnesium oxide, silver oxide and barium oxide; alkalimetal and alkalineearth metal carbonates such as sodium carbonate, potassium carbonate,magnesium carbonate, calcium carbonate and barium carbonate, and ammoniaand ammonia producing compounds such as ammonium hydroxide and ammoniumcarbonate; and organic bases, for example, aliphatic and aromaticalkoxides such as sodium methoxide, potassium methoxide, lithiummethoxide, sodium ethoxide, potassium ethoxide, lithium butoxide, sodiumbutoxide, sodium phenoxide, lithium phenoxide and potassium phenoxide;tertiary amines such as trirnethylamine, triethylamine,tri-npropylamine, triisopropylamine, tri-n-butylamine, triisobutylamine,tri-sec-butylamine, tri-n-amylamine, triisoamylamine, trihcxylamine,triheptylamine and trioctylamine, other tertiary amines such as pyridineand mercaptides such as sodium methylmercaptide, sodium ethylmercaptide,potassium methylmercaptide and potassium phenylmercaptide.

The following examples will illustrate the invention. Parts and percents are by weight unless otherwise indicated.

EXAMPLE 1 A suitable reaction vessel is charged with about 70 parts ofbenzene, 25 parts of methyltrichlorosilane and 44 parts ofethylacetimidate dissolved in 51 parts of triethylamine. The mixture isheated at reflux with stirring for about 2 hours. At the end of thistime the amine hydrochloride is removed by filtration and the filtrateis concentrated by evaporation of the benzene. The concentrate isfiltered to give 35 parts of methyl-tris-(ethylacetimidato )-silane, aliquid having a b.p. of l32 to 134 C at a pressure of 0.6 mm of mercury.The product imidatosilane is confirmed by nuclear magnetic resonance(NMR) and infrared analysis lR).

Following substantially the same procedure as in the fore going exampleand using the appropriate reactants, the following ss o f h inventiontsnrsnsrsqr a- EXAMPLE i QY B9QP 2. Methyl-tris(ethyldirnethylcyanimidato )silane.Methyl-tris(ethyldiethylcyanimidato)silane. Methyl-tris(ethyldiethylcyanimidato )silane. Phenyl-tris( ethyldiethyleyanimidato)silane. Phenyl-tris( ethyldimethylcyanimidato )silane. Ethyl-tris(ethyldimethylcyanimidato )silane. 8. nPropyl-tris(ethyldimethylcyanimidato )silane. 9. Methyl-tris(isopropylpropionimidato )silane. Methyl-tris( ethylpropionimidato)silane. Phenyl-tris( ethylpropionimidato )silane.Phenyl-tris(n-butylpropionimidato)silane.Phenyl-tris(chloromethylpropionimidato )silane. Phenyl-tris(phenylpropionimidato )silane. Phenyl-tris( 2-chlorophenylpropionimidato)silane. Methyl-tris(ethylacetimidato )silane. tris(ethylacetimidato)silane. Methyl-tris(n-butylacetimidato )silane.Methoxy-tris(phenylacetimidato)silane. Butoxy-tris(ethylacetimidato)silane. Butoxy-tris( n-propylacetimidato)silane.Phenyl-tris(ethylacetimidato)silane. Phen yl-tris( propylacetimidato)silane. tetra-( ethylacetimidato )silane.

EXAMPLE 25 V A suitable reaction vessel is charged with about 375 partsof benzene, 149 parts of methyltrichlorosilane, 46 parts of ethylalcohol and 174 parts of ethyl acetimidate dissolved in 303 parts oftriethylamine. The reaction mixture is heated at reflux with stirringfor about 2 hours. At the end of this time the amine hydrochloride isremoved by filtration and the filtrate concentrated by evaporation ofthe benzene. The concentrate is filtered to give 172 parts ofmethyl(ethoxy)-bis- (ethylacetimidato)silane, a liquid having a b.p. ofto 86 C at a pressure of 0.6 mm of mercury. The product imidatosilane isconfirmed by IR.

EXAMPLE 26 A suitable reaction vessel is charged with about 3 30 partsof benzene, 149 parts of methyltrichlorosilane, 92 parts of ethylalcohol and 87 parts of ethyl acetimidate dissolved in 303 parts oftriethylamine. The reaction mixture is heated at reflux with stirringfor about 2 hours. At the end of this time the HCl is removed byfiltration and the filtrate concentrated by evaporation of the benzene.The concentrate is filtered to give 1 10 parts ofmethyl-(diethoxy)(ethylacetimidato)silane, a liquid having a b.p. of 60to 65 C at a pressure of 0.6 mm of mercury. The product imidatosilane isconfirmed by IR.

Following substantially the same procedure as in Examples 25 and 26 andusing the appropriate reactants, the following compounds of thisinvention are prepared.

"EXAMPLE COMPOUND 27. Methoxy(t-butoxy)-bis(phenylpropionimidato)silane.

. Methyl(ethoxy)-bis( methylpropionimidato)silane. Methyl(methoxy)-bis(ethylpropionimidato)silane. Methyl( n-butoxy )-bis( ethylpropionimidato)silane. Methyl(t-butoxy)-bis(phenylpropionimidato)silane.Methy1(t-butoxy)-bis( ethylacetimidato)silane.

. Phenyl(t-butoxy)-bis(ethylacetimidato)silane.

. Ethyl(t-butoxy)-bis(ethy1acetimidato)silane.

. Phenyl(methoxy)-bis(propylacetimidato )silane.

. Phenyl( ethoxy)-bis(ethylacetimidato)silane.

. t-Butyl(ethoxy )-bis( ethylacetimidato)silane.

. Methoxy(methoxy)-bis( ethylacetimidato)silane.

. Methyl(methoxy)-bis( ethylacetimidato)silane.

. Phenyl(methoxy)-bis(ethylacetimidato)silane.

. Methyl(dimethoxy)(ethylacetimidato)silane.

. Methoxy(diethoxy)(ethylacetimidato)silane.

. Methoxy(diethoxy)(ethylacetimidato )silane.

. Methoxy(di-t-butoxy)( ethylacetimidato)silane.

. Phenyl(di-t-butoxy)(ethylacetimidato)silane.

. Phenyl(dimethoxy)(ethylacetimidato)si1ane.

. Pheny1(diphenoxy)(ethylacetimidato)silane.

. Methyl(dimethoxy)(phenylpropionimidato )silane.Methyl(diphenoxy)(methylpropionimidato)silane.

The imidatosilanes of the above formula wherein d and/or e are zero areuseful in the preparation of room temperature vulcanizing compositionswhich are stable under substantially anhydrous conditions and which cureto the solid, elastic state upon exposure to moisture.

The RTV compositions comprise an admixture of one or more imidatosilanesof the above formula wherein d and/or e are zero and a silanolchain-stopped polydiorganosiloxane represented by the formula wherein Rand R are each organic radicals of not more than 18 carbon atomsselected from the group consisting of hydrocarbyl, halohydrocarbyl andcyanoalkyl, and n is an integer of at least 5 and is generally fromabout 10 to about 15,000 or more.

The silanol chain-stopped polydiorganosiloxanes are well known in theart and include compositions containing different R and R groups. Forexample, the R groups can be methyl, while the R groups can be phenyland/or betacyanoethyl. Furthermore, within the scope of thepolydiorganosiloxanes which can be employed are copolymers of varioustypes of diorganosiloxane units, such as silanol chainstopped copolymersof dimethylsiloxane units, diphenylsiloxane units andmethylphenylsiloxane units or, for example, copolymers ofdimethylsiloxane units, methylphenylsiloxane units andmethylvinylsiloxane units. It is preferred that at least 50 percent ofthe R and R groups of the silanol chainstopped polydiorganosiloxanes bemethyl groups. A mixture of various silanol chain-stoppedpolydiorganosiloxanes also can be employed. The silanol chain-stoppedmaterials useful in the RTV compositions have been described aspolydiorganosiloxanes but such materials can also contain minor amounts,e.g., up to about 1.0 percent of monoorganosiloxane units such asmonoalkylsiloxane units, e.g., monomethylsiloxane units andmonophenylsiloxane units, and mono-t-alkoxysiloxane units, e.g.,mono-t-butoxysiloxane units and mono-tpentoxysiloxane units; andtriorganosiloxane units, such as trialkylsiloxane units, e.g.,trimethylsiloxane units, tributylsiloxane units and triphenylsiloxaneunits, and tri-t-alkoxysilane units, e.g., tri-t-butoxysiloxane unitsand tri-t-pentoxysiloxane units. Many of the tri-t-alkoxysilanes usefulas part of the silanol chain-stopped materials are described and claimedin application Ser. No. 634,828 filed May 1, 1967, the disclosure ofwhich is expressly incorporated herein by reference.

The silanol chain-stopped polydiorganosiloxanes useful in the RTVcompositions can vary from thin fluids to viscous gums, depending uponthe value of n and the nature of the particular organic groupsrepresented by R and R". Preferably, the silanol chain-stoppedpolydiorganosiloxane will have a viscosity in the range of aboutcentipoise to about 50,000 centipoise at 25 C.

The RTV compositions are prepared by mixing one or more of theimidatosilanes with the silanol chain-stopped polydiorganosiloxane.Since the imidatosilanes will hydrolyze upon contact with moisture, careshould be exercised to exclude moisture during the addition of theimidatosilane to the silanol chain-stopped polydiorganosiloxane.Likewise, care should be taken that the mixture of the imidatosilane andthe silanol chain-stopped polydiorganosiloxane is maintained undersubstantially anhydrous conditions if it is desired to store the mixturefor an extended period of time prior to conversion of the material tothe cured, solid, elastic silicone rubber state. On the other hand, ifitis desired to permit the mixture to cure immediately upon addition ofthe imidatosilane to the polydiorganosiloxane, no special precautionsare necessary and the two components can be admixed and placed in theform or shape in which it is desired for the composition to be cured.

The amount of the imidatosilane admixed with the silanol chain-stoppedpolydiorganosiloxane can vary within wide limits. However, for bestresults, it is preferred to add an excess of one mole of theimidatosilane per mole of siliconbonded hydroxyl groups in the silanolchainstopped polydiorganosiloxanes. Satisfactory curing can be obtained,for example, with from 1.0 to 4 moles of the imidatosilane per mole ofsilicon-bonded hydroxyl groups in the polydiorganosiloxane. Noparticular benefit is derived from using more than 4 moles of theimidatosilane per mole of the polydiorganosiloxane. The temperature ofthe addition of the imidatosilane to the silanol chainstoppedpolydiorganosiloxane is not critical, and a temperature from about 20 Cto about 80 C is usually employed.

The RTV compositions exhibit improved properties in the cured state ascompared to known RTV compositions, particularly in the areas ofnon-corrosion, thick section cure and adhesion to substrates. Improvedadhesion to substrates such as concrete, glass, wood and aluminum isobtained with the present RTV compositions. Most importantly, theimproved adhesion is achieved without the use of expensive andtimeconsuming primers. The RTV compositions can be used underenvironmental conditions where the use of certain known RTV compositionsis not without possible harmful effects from corrosion. Finally, many ofthe RTV compositions give a more satisfactory cure of thick sectionsthan is possible with known RTV compositions.

EXAMPLE 50 A suitable reaction vessel containing about 926 parts oftoluene and about 174 parts of ethylacetimidate is charged with aboutparts of dimethyldichlorosilane. The mixture is stirred for about 5minutes at room temperature and about 202 parts of triethylamine areadded. The mixture is heated at 80 C for 2 hours, cooled to 30 C andfiltered to remove the amine hydrochloride. The filtrate is concentratedby evaporation to remove the toluene and is subjected to flashdistillation to give 138 parts of dimethyl-bis-(ethylacetimidato)silanehaving a b.p. of 101 C at a pressure of 9 mm of mercury. The productimidatosilane is confirmed by NMR and IR.

Following substantially the same procedure as in Example 50 above andusing the appropriate reactants, the following compounds of thisinvention are prepared.

EXAMPLE COMPOUND 5 1. Diethyl-bis(ethylacetimidato)silane. 52.Dipropyl-bis( ethylacetimidato )silane. 53. Di-t-butyl-bis(ethylacetimidato )silane. 54. Diphenyl-bis(ethylacetimidato)silane. 55.Diethyl-bis(phenylacetimidato)silane.

The imidatosilanes of this invention wherein d and e are each 1 areuseful as chain extenders for silanol-stopped diorganosiloxane fluidsand as process aids for RTV compositions. A small amount of thedihydrocarbyl containing imidatosilanes, when added to RTV compositions,markedly reduce structuring of the rubber.

EXAMPLE 56 An RTV composition comprising about 44 parts of asilanol-stopped polydimethylsiloxane having a viscosity of 3,000centipoises at 25 C and 56 parts of a silanol-stoppedpolydimethylsiloxane having a viscosity of 20,000 centipoises at 25 C isadmixed with 1.5 parts of dimethyl-bis- (ethylacetimidato)silane and0.08 part of dibutyl tin dilaurate, stirred for 30 minutes and heated to60 C. A silazane treated silica filter, 28 parts, and 15 parts of astandard plasticizer are added to the mixture. Mixing is continued foran additional 2 hours at room temperature at which time 6 parts ofmethyltris(ethylacetimidato)silane is added as curing agent. The uncuredcomposition is applied from an 8 oz. caulking cartridge under 90 psi ata rate of 43 grams/minute. The same composition without thedimethyl-bis(ethylacetimidato)silane is applied from an 8 oz. caulkingcartridge under 90 psi at an application rate of only 3 grams/minute.

The imidates useful in the preparation of the imidatosilanes of thisinvention are well known in the art and can be prepared by severalmethods. One method comprises reacting a nitrile with an alcohol in thepresence of an acid such as HC] and then treating the resulting saltwith a base such as K CO in a solvent such as methylene chloride inorder to obtain the free base.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. Compound of the formula:

wherein R and R" are each radicals of not more than 9 carbon atomsselected from the group consisting of hydrogen, hydrocarbyl,halohydrocarbyl and cyanoalkyl, R and R are each organic radicals of notmore than nine carbon atoms selected from the group consisting ofhydrocarbyl,

halohydrocarbyl, and alkoxyhydrocarbyl, R is a radical of not more thannine carbon atoms selected from the group consisting of hydrogen,hydrocarbyl, and diaikylamino. a is an integer of l to 4, inclusive, bis an integer of 0 to 3, inclusive, 0! and e are each integers ofO to l,and the sum ofa, b, d and e is 4.

2. Compound of claim 1 wherein R, R, R, R and R are alkyl.

3. Compound of claim 1 wherein R. R. R and R are alkyl. 1: is l and e iszero.

4. Compound of claim 1 wherein R, R and R are alkyl. and b and e arezero.

5. Compound of claim 1 wherein R and R are alkyl, R is dialkylamino, andb and e are zero.

6. Compound of claim 1 wherein R and R are alkyl, R is dialkylamino, Ris alkyl and e is zero.

7. Compound of claim 1 wherein R and R are alkyl, R is dimethylamino, Ris alkyl and e is zero.

8. Compound of claim 1 wherein R and R are methyl, R and R are ethyl ande is zero.

9. Compound of claim 1 which ismethyl-tris(ethyldimethylcyanimidato)silane.

10. Compound of the formula:

wherein R, R, R, R and R" are alkyl radicals of l to 9 carbon atoms, ais an integer of l to 4, inclusive, b is an integer of 0 to 3,inclusive, d and e are each integers of 0 to l, and the sum of a, b, d,and e is 4.

11. Compound of claim tris( ethylacetimidato )silane.

12. Compound of claim 10 which is methyl-tris(isopropylpropionimidato)silane.

13. Compound of claim 10 which is methyl(ethoxy)-bis-(ethylacetimidato)silane.

14. Compound of claim 10 which is methyl(isopropoxy)-bis(isopropylpropionimidato )silane 15. Compound of claim 10 which ismethyl( diethoxy)- ethylacetimidatosilane.

16. Compound of claim 10 which is methyl( diisopropoxy)-isopropylpropionimidatosilane.

* IIK it i 10 which is methyl-

2. Compound of claim 1 wherein R, R1, R2, R3 and R7 are alkyl. 3.Compound of claim 1 wherein R, R1, R2 and R3 are alkyl, b is 1 and e iszero.
 4. Compound of claim 1 wherein R, R1 and R3 are alkyl, and b and eare zero.
 5. Compound of claim 1 wherein R and R1 are alkyl, R3 isdialkylamino, and b and e are zero.
 6. Compound of claim 1 wherein R andR2 are alkyl, R3 is dialkylamino, R1 is alkyl and e is zero.
 7. Compoundof claim 1 wherein R and R2 are alkyl, R3 is dimethylamino, R1 is alkyland e is zero.
 8. Compound of claim 1 wherein R1 and R3 are methyl, Rand R2 are ethyl and e is zero.
 9. Compound of claim 1 which ismethyl-tris(ethyldimethylcyanimidato)silane.
 10. Compound of theformula: wherein R, R1, R2, R3 and R7 are alkyl radicals of 1 to 9carbon atoms, a is an integer of 1 to 4, inclusive, b is an integer of 0to 3, inclusive, d and e are each integers of 0 to 1, and the sum of a,b, d, and e is
 4. 11. Compound of claim 10 which ismethyl-tris(ethylacetimidato)silane.
 12. Compound of claim 10 which ismethyl-tris(isopropylpropionimidato)silane.
 13. Compound of claim 10which is methyl(ethoxy)-bis-(ethylacetimidato)silane.
 14. Compound ofclaim 10 which is methyl(isopropoxy)-bis(isopropylpropionimidato)silane.15. Compound of claim 10 which ismethyl(diethoxy)-ethylacetimidatosilane.
 16. Compound of claim 10 whichis methyl(diisopropoxy)-isopropylpropionimidatosilane.